This invention relates to a film folding control apparatus of a wrapping system in which articles accommodated in individual trays are wrapped in a stretchable film on a tray-by-tray basis.
A variety of wrapping machines are known in the art for introducing articles into tray-shaped containers (hereafter referred to simply as trays) and wrapping each tray in a stretchable film. The applicant has already developed a wrapping machine in which a length of film fed by a film feeding mechanism is extended at a predetermined section of the wrapping machine, an article to be wrapped is raised into taut engagement with the extended film from therebelow, and the edges of the film are folded under the bottom of the article, thereby wrapping the article in the film, by means of a film folding mechanism comprising left, right and front folding plates. Inventions claiming various aspects of this wrapping machine have been filed with the Japanese Patent Office as Japanese Utility Model application Nos. 59-133273 and 59-133274, and Japanese patent application No. 59-182466.
In the wrapping machine having the foregoing construction, the final appearance of the wrapped articles depends upon such factors as the size, material, shape and dimensions of the tray into which the articles are introduced. In order to improve the appearance of a packaged wrapped by the aforementioned wrapping machine, the applicant has also developed a film folding control apparatus, filed with the Japanese Patent Office as Japanese patent application No. 60-24686, in which the length to which the film is cut, the amount of tension applied to the film and the tray type can be set at a control panel through use of switches denoted by SW1, SW2, SW3 in the specification of the cited application.
With the above film folding control apparatus used in the wrapping machine of the type described, the fact that film cut length, tension and tray type can be set by the switches SW1, SW2, SW3 at the control panel enables the final appearance of the wrapped packages to be improved and makes it possible to reduce wasteful use of the film. However, in actually using the wrapping machine to wrap articles, the operator must make the above settings by manipulating each one of the switches SW1, SW2, SW3 whenever the type of article to be wrapped is changed. This is a troublesome task which detracts from the efficiency of the machine. Moreover, the particular values to which the film cutting length, tension and tray type are to be set depending upon the type of article to be wrapped must either be memorized by the operator himself or written in the form of a list affixed to a surface in the vicinity of the machine and referred to each time a setting is to be made. Both of these expedients are inconvenient.